Tamping plug for use in blasting



Jan. 15 1924.

A. COCKBURN TAMPING PLUG FOR USE IN BLASTING Y Filed July 28. 1925 Patented Jan. 15, 1924.

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Application filed 51115 .28, 1923'. Serial No. 65%475.

T all whom it may concern:

Be it known that I, ARTHUR CooKBURN, a subject of the King of Great Britain, residing at Cullinan Buildings, Simmonds Street, Johannesburg, Transvaal, South Africa (whose post-ofiice address is Box 668, Johannesburg, Transvaal), have invented a certain new and useful Improvement in Tamping Plugs for Use in Blasting, of which the following is a specification.

This invention relates to tamping plugs or checks for use in blasting and has more particular reference to plugs or checks of that type comprising two wedge members having 5 their inclined faces fitted together so that the force of the explosion serves to wedge the said members more tightly in the hole within which they are fitted. The object of the present invention is to provide an improved form of tamping plug or check of this type which is of simplified construction, and therefore less costly to manufacture.

Tamping checks are known which are of cylindrical form and depend for their action on the fact that the two portions comprising the check coact with one another, when the explosion takes place, to exert a w wedging action tending to increase the 3H diameter of the check which is, accordingly, wedged more firmly in the hole. The fuse has been accommodated in a hole drilled, or otherwise formed, through the whole length of the check and this accounts, in the main, for the cost of manufacture and, in addition, causes loss of time in actual use, which is incurred through the necessity of threading the fuse through the hole.

According to the present invention, a cylindrical check is provided for insertion after the tamping, said check consisting of a cylinder which has had a portion removed longitudinally along a plane parallel with the axis, in order to accommodate the fuse; the resulting portion being split along its length along a plane at right angles to the plane before-mentioned and making an angle with the axis of the cylinder such that two wedges are formed, the sloping faces of which extend the whole length of the cylinder.

In the actual manufacture, any method may be adopted to produce the sahne shape consistent with cheapness,

It will be seen that the fuse is carried in such a position, owing to, the fact that the sloping faces of the wedges are at right angles to the face against which the fuse rests, that no force can be exerted upon it due to the wedging action which takes place when pressure is applied to the check axially, and the passage for the fuse can be made at very much less expense by merely removing a portion of the surface of the check than by forming a hole or a groove therein. Moreover, the area of contact with the wall of the hole is not reduced to such an extent as will affect the retaining action of the wedge.

The essence of the invention lies in the fact that the flat surfaces on the two wedgeshaped portions, which form. one surface when the wedge is assembled, are in a plane at right angles to the plane of contact be tween the said wedge-shaped portions, thus avoiding the danger of squeezing the fuse between the check and the wall of the hole, the chief disadvantage of such squeezing being that when the fuse is burnt the check becomes loose in the hole. The flat surface on the check is made as small as possible, consistent with the provision of a passage of sufficient width to accommodate the fuse.

The invention is illustrated in the accompanying drawings in which:

Fig. I shows the two wedge portions separated.

Fig. 11 shows the two wedges together in the form in which they are introduced into the hole. 1 is a plane along which a portion has been removed parallel with the axis of the cylinder and 2 is a plane at right angles to plane 1 and at an angle to the axis so as to form two wedge shaped complemental members.

The space between the plane 1 and the face of the hole in which the tamping check is fitted affords a passage for the fuse which is free from any possibility of damage due to the explosion which wedges the check more firmly in the hole.

Such wedging action, however, does not tend to force the wedge against the fuse since the forces tending to expand the check act parallel to the plane 1.

The two wedges are held together by a paper band 3 or they may be held together by reason of the cylinder not being completely severed into two portions, the uncut reversely-arranged Wedge-shaped members; snbstantlally as described.

2. A cylindrical check for insertion after 15 tamping, comprising a pair of complemental, reVersely-arranged Wedge portions in which the passage for the fuse is provided by a flat surface on the check in a longitudinal plane. at right angles to the plane of 20 contact between the said wedge portions.

Signed at Johannesburg this twentieth day of June, 1923.

ARTHUR COCKBURN. 

